function add(arg1,arg2){
    let t1 = 0
    let t2 = 0
    if(arg1.toString().indexOf('.')>-1){
        //第一个参数的小数位数
        t1 = arg1.toString().split('.')[1].length
    }
    if(arg2.toString().indexOf('.')>-1){
        //第一个参数的小数位数
        t2 = arg2.toString().split('.')[1].length
    }
    //取得最长小数
    let m = Math.pow(10,Math.max(t1,t2))
    let result = (arg1*m + arg2*m) / m
    return result
}
function mul(arg1,arg2){
    let a1=arg1.toString()
    let a2=arg2.toString()
    let m = 0
    if(a1.indexOf('.')>-1){
        //第一个参数的小数位数
        m += a1.split('.')[1].length
    }
    if(a2.indexOf('.')>-1){
        //第一个参数的小数位数
        m += a2.split('.')[1].length
    }

    return Number(a1.replace('.','')) * Number(a2.replace('.','')) / Math.pow(10,m)
}
function sub(arg1,arg2){
    let t1 = 0
    let t2 = 0
    if(arg1.toString().indexOf('.')>-1){
        //第一个参数的小数位数
        t1 = arg1.toString().split('.')[1].length
    }
    if(arg2.toString().indexOf('.')>-1){
        //第一个参数的小数位数
        t2 = arg2.toString().split('.')[1].length
    }
    let m = Math.pow(10,Math.max(t1,t2))
    let result = (mul(arg1,m)-mul(arg2,m))/m
    return result
}
function div(arg1,arg2){
    let t1 = 0
    let t2 = 0
    let a1 = arg1.toString()
    let a2 = arg2.toString()
    if(a1.indexOf('.')>-1){
        t1 = a1.split('.')[1].length
    }
    if(a2.indexOf('.')>-1){
        t2 = a2.split('.')[1].length
    }
    let r1 = Number(a1.replace('.',''))
    let r2 = Number(a2.replace('.',''))
    let result = mul(r1/r2,Math.pow(10,t2-t1))
    return result
}
module.exports = {
    add,mul,sub,div
}